Leg structure



Jan. 6, 1970 v J. LEWANDOWSKI ET L LQEG STRUCTURE 2 Sheets-Sheet 1 FiledApril 22, 1968 INVENTORS.

JOSEPH LEWANDOWSKI ROBERT LA PATTA JOHN P. CHANDLER THEIR ATTORNEY.

J. LEWANDOWSKI ET AL 35488,@@?

Jan, 1970 LEG STRUCTURE 2 Sheets-Sheet 2 Filed April 22. 1968 INVENTORS.JOSEPH LEWAN DOWSKI B4'3OBERT LA PATTA JOHN PFCHANDLER THEIR ATTORNEY.

United States Patent 3,488,697 LEG STRUCTURE Joseph Lewandowski,Franklin Park, and Robert La Patta, Annandale, N.J., assignors toFederal Steel Corporation, New York, N.Y., a corporation of New JerseyFiled Apr. 22, 1968, Ser. No. 723,080 Int. Cl. F16m 11/16 US. Cl.248-188 8 Claims ABSTRACT OF THE DISCLOSURE A tubular leg, the leg beingupset at its upper end with a die, forming a plurality of jaws spacedfrom each other and from the leg axis, and providing a central verticalrecess to receive a thread cutting screw to secure the leg to a tabletop, each jaw having an outer face which is curved upwardly andinwardly, and walls extending radially inwardly from each side of thejaw, providing vertical edges for the thread cutting screw.

SUMMARY OF THE INVENTION The tubular leg is struck with a die of specialconfiguration which crushes the metal of the leg end inwardly and formsa plurality of jaws, usually four, which are spaced from each other andfrom the leg axis, forming eight generally straight radial walls withinner edges, two on :each jaw, which receive the screw which cuts itsown thread and secures the leg to the table top or other article with noreasonable possibility of pull out.

OBJECTS OF THE INVENTION An important object of the invention is toprovide an inexpensive leg attaching construction formed by a singleblow from a die and having great resistance to pull out from theattaching screw. The leg end with its multiple jaw formation has a conedrather than flat end face and, in one application, it is used inconjunction with a cone shaped cup of the kind disclosed in Patent No.3,111,337 wherein the cup has a central hole that receives the leg. Thisleg has an annular stop or rib below the top of the leg a distanceslightly less than the height of the cone. The top of the leg isaccordingly spaced from the lower face of the table top, or bowl of acharcoal grill, while the upper annular rim of the cone engages thislower face. A screw passes downwardly through a hole in the top and intoa nut element at the upper end of the leg, and, upon being tightened,pulls the top of the leg upwardly but the parts are so proportioned thatit never quite touches the bowl. The upper rim of the cone provides anannular brace clear around the top of the leg but spaced far enough fromthe central screw to provide a very effective support, when the screw istightened full up, against forces diiected horizontally against thelower end of the leg.

In the event that the use is such that there are no forces tending todisrupt this leg from its position normal to the table top, or in theevent that the leg is braced by other means, a goodly measure of supportagainst lateral displacement may be provided by a simple tubular adapterreceived in the leg end, limited on downward travel by the annular beadearlier mentioned, and having a square upper end lying above the conedupper end of the leg. When the screw is tightened, the square end of theadapter is drawn tightly against the underside of the table top.

Another object of the invention is to provide a firm and secure joint,right angular or otherwise, between two tubular members, as in tubularmetal furniture construction. The short adapter, instead of having asquare end, has a concave end which receives the right angular memberwith a screw passing through both walls of the latter tube and into thecentral thread section of the jaws. This construction is especiallyadapted for securing a horizontal foot to the vertical leg of a foldingironing board. The entire joint is neat and trim in appearance, it isstronger than a welded construction, and if looseness ever develops thetrouble is corrected by tightening this screw.

In the drawings:

FIG. 1 is a broken side elevation of a leg embodying the presentinvention as secured to a table top;

FIG. 2 is a top plan view of the leg structure;

FIG. 3 is a section taken on line 33 of FIG. 2;

FIG. 4 is a section taken on line 44 of FIG. 2;

FIG. 5 is a section taken through a modification of the presentinvention;

FIG. 6 shows another modification;

FIG. 7 is a plan view of the die used in forming the leg structure;

FIG. 8 is a section taken on line 88 of FIG. 7;

FIG. 9 is a section taken on line 9-9 of FIG. 7;

FIG. 10 is a lower plan View of the die structure, the view being takenon line 1010 of FIG. 8;

FIG. 11 is an exploded View showing the component parts of the die.

The tubular leg 10 of the present invention with its upset upper end,forming jaws, to receive therebetween a thread cutting screw 11 is shownin FIG. 1. The construction of the upsetting die, later to be described,lends itself to the formation of four jaws. By modifying the die anynumber can be formed. The jaws have slots 12 between them. Each jaw hasan outer face 13 which is curved upwardly and inwardly and the opposededges of each jaw are bent radially inwardly forming radial walls 14 andat their inner ends two generally straight edges 16 which are parallelwith the axis to receive the thread cutting screw that secures the legto a horizontal member such as as a table top 17 or a bowl fora charcoalbroiler. Each pair of edges 16 are in substantial meeting engagement andhave no preformed notches for the threads.

Between each pair of adjoining jaws 12 there is a curved lower wall 18which extends inwardly from the outer periphery of the tube and whichterminates in a short edge 19, the several edges forming a centralopening indicated by broken lines 20 to receive the lower end of thescrew 11. There would be no objection to tapping this opening and thusproviding pro-formed threads for the screw. This is not necessary,however, and the eight untreated edges provide excellent stock for theforming of the thread, shown at 21 as the screw it rotated. The jawswith their radial walls 14 do not bend rearwardly as the screw entersthe hole, thus insuring against pull-out.

The leg has an annular bead or rib 15 forming a stop for the cone 9.This head is so located on the leg, in relation to the height of thecone that the upper ends of the jaws are always spaced from the lowerface of the table top and this permits as much tightening of the screwas the strength of the parts permit.

In the modified leg joint of FIG. 5, a short tubular section 8 replacesthe cone shaped cup 9. This arrangement does not give as much lateralsupport to the lower end of the leg but is nevertheless quite effective.

In the second modification shown in FIG. 6, the tubular member 10 withthe jaws 13 formed as just described is to be secured in rigid relationto another tubular member 22 at right angles to tube 10. A short tubularsection or adapter 23 is carried on member and engages the annular beadat its upper end and the opposed lower edges of the round adapter areconcavely curved as shown at 24, the curvature fitting the outside oftubular member 22. When screw 11 located in aligned holes 25 in tube 22cuts threads in the jaws and is tightened there is provided a very firmright angular connection between the members. By modifying the shape ofconcave edges 24, the angularity between tubes 10 and 22 are varied. Insuch case, the holes 25 will be offset from each other an approveddistance.

The die assembly includes a ring-like die carrier 24 having a centralbore 26 of such size as to snugly receive the leg 10. The lower face ofthe die carrier is externally bevelled at 28. The bore has a counterbore29 forming a shoulder 30 and the lower end 31' of the forming die 31rests upon this shoulder. The forming die has a solid upper sectionwhich is substantially plane with the upper face of the die carrier andhas a concave recess 32 to shape the outer curved facees of the jaws 13.The lower end of the forming die has cross slots 34 extending clearacross and about of the distance towards the top and which receive apair of die blades 35 and 36 to form the slots in right angular relationwith complementary lower and upper slots 37 and 38 in which the centralland portions of the blades are received. The lower edges of the dieblades have a pair of arcuate edges 39 extending to a central V-shapedportion 40.

While there have been described herein what are at present consideredpreferred embodiments of the invention, it will be obvious to thoseskilled in the art that many modifications and changes may be madetherein.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A tubular leg which is upset at its upper end with a die, forming aplurality of jaws spaced from each other and from the leg axis, andproviding a central vertical recess to receive a screw to secure the legto a table top or the like, each jaw having an outer face which iscurved upwardly and inwardly, and walls extending radially inwardly fromeach side of the jaw, thus providing two vertical edges on each jawwhich are in substantially meeting relation and on which threads toreceive the screw are formed.

2. The leg structure of claim 1 wherein short walls connect each pair ofjaws at the ends thereof.

3. The leg structure of claim 1 wherein said vertical edges are intiallysubstantially straight and the SCIEWZlS a thread cutting screw whichforms notches for threads by said screw.

4. The leg of claim 1 wherein an annular head is formed on the leg at apoint spaced from its upper end.

5. The leg of claim 4 for securing to said table top or the like whereinsaid screw passes through said table top and into the central verticalrecess and a cone of greater height than the distance from the annularhead to the upper end of the leg receives the leg and braces it in aposition normal to the table top when the screw has been tightenedwithin the vertical recess and against the table top.

6. The leg structure of claim 4 for securing to a table top or the likewherein said screw passes through said table top and into the centralvertical recess and a tube of greater height than the distance from theannular head to the leg top receives the leg and braces it in a positionnormal to the table top when the screw has been tightened within therecess and against the table top.

7. The tubular structure of claim 4 and another tubular structure lyingat an angle to the first structure is secured thereto, a relativelyshort tube contoured at one end to fit the exterior of the fixed tubularstructure is carried on said first tubular structure and engages thebead at its opposite end and wherein the short tube has a length greaterthan the distance from the attaching end of said first tubular structureto said bead and a screw passes through the short tube and into saidcentral recess.

8. The structure of claim 4 wherein the two tubular structures have aright angular relation to each other.

References Cited UNITED STATES PATENTS r MARION PARSONS, JR., PrimaryExaminer US. Cl. X.R. 32; 28720

